In some states, these powers are partly or mostly devolved to the counties'
smaller divisions usually called
townships, though in New York, New England and Wisconsin they are called "towns". The county may or may not be able to override its townships on certain matters, depending on the
state constitution.

Similarly, some of
Alaska's boroughs have merged with their principal cities creating unified city-boroughs. Some such consolidations and mergers have created cities that rank among the geographically largest cities in the world, though often with population densities far below those of most urban areas.

County equivalents

The term county equivalents is used to describe divisions whose organization differs from that of most counties:

Alaska census areas: Most of the land area of Alaska is not contained within any of Alaska's 19 organized boroughs. This vast area, larger than
France and
Germany combined, is officially referred to by the Alaska state government as the Unorganized Borough and outside of other incorporated borough limits, has no independent "county" government, although several incorporated city governments exist within its boundaries; the majority of it is governed and run by the State of Alaska as an extension of state government.[b] The
United States Census Bureau, in cooperation with the Alaska state government for census and electoral districting purposes, has divided the Unorganized Borough into 11 census areas for statistical purposes only.[c]

Independent cities: These are cities that legally belong to no county. They differ from consolidated city-counties in that in the case of a consolidated city-county, the county at least nominally exists, whereas in the case of an independent city, no county even nominally exists. As of July 2013[update], there are 41 such cities in the United States, including
Baltimore, Maryland;
Carson City, Nevada;
St. Louis, Missouri; and all 38 cities in
Virginia, where any area incorporated as a city is outside of the county jurisdiction.[18][19]

Washington, D.C.,[20] outside the jurisdiction of any state, has a special status. The city of Washington comprises the entirety of the
District of Columbia, which, in accordance with Article 1, Section 8 of the
U.S. Constitution, is under the jurisdiction of the
U.S. Congress. When founded in 1801, the District consisted of two counties and three cities. In 1846,
Alexandria County (which now forms
Arlington County and a portion of the independent city of
Alexandria)—including the then City of Alexandria—was given back to Virginia. In 1871, the three remaining entities—the City of Washington,
Georgetown City, and
Washington County (which was coterminous with the District)—were merged into a consolidated government by an act of Congress. Georgetown was abolished as a city by another act in 1895.

Consolidated city-counties are not designated county-equivalents for administrative purposes; since both the city and the county at least nominally exist, they are properly classified as counties in their own right. The same is true of the
boroughs of New York City, each of which is coextensive with a county of New York State.

Territories

There are no counties per se in U.S. territories.
American Samoa has
its own counties, but the U.S. Census Bureau does not count them as counties (instead, the U.S. Census Bureau counts American Samoa's
3 districts and 2 atolls as county equivalents).[5][6] American Samoa's counties are treated as minor civil divisions.[6] Most territories are directly divided into municipalities or similar units, which are treated as equivalent of counties for statistical purposes:[5][2][6][21]

Organization

The site of a county's administration, and often the county
courthouse, is called the
county seat ("parish seat" in Louisiana, or "borough seat" in Alaska). Several
New England counties use the term "
shire town" for the county seat.

Many counties are divided into smaller political or governmental units. In Northeastern and Midwestern states, counties are divided into
civil townships (or "towns" in New England, New York, and Wisconsin), which may provide governmental or public services.

County names

Common sources of county names are names of people, geographic features, places in other states or countries, Native American tribes, and animals. Quite a few counties bear names of French or Spanish origin.[24]

After people, the next most common source of county names are geographic features and locations, with some counties even being named after counties in other states, or for places in countries such as the United Kingdom. The most common geographic county name is
Lake. Native American tribes and animals lend their names to some counties. Quite a few counties bear names of French or Spanish origin, including
Marquette County being named after French missionary
Father Jacques Marquette.[24]

The county's equivalent in the state of Louisiana, the
parish (Fr. paroisse civile and Sp. parroquia) took its name during the state's French and Spanish colonial periods. Before the
Louisiana Purchase and granting of statehood, government was often administered in towns where major church
parishes were located. Of the original 19 civil parishes of Louisiana that date from statehood in 1807, nine were named after the Roman Catholic parishes from which they were governed.

In most Midwestern and Northeastern states, counties are further subdivided into
townships or
towns, which sometimes exercise local powers or administration. Throughout the United States, counties may contain other independent, self-governing
municipalities.

In many states, the board in charge of a county holds powers that transcend all three traditional branches of government. It has the legislative power to enact ordinances for the county; it has the executive power to oversee the executive operations of county government; and it has quasi-judicial power with regard to certain limited matters (such as hearing appeals from the planning commission if one exists).

The day-to-day operations of the county government are sometimes overseen by an elected
county executive or by a chief administrative officer or
county administrator who reports to the board, the mayor, or both.

In many states, several important officials are elected separately from the board of commissioners or supervisors and cannot be fired by the board. These positions may include
county clerk, county
treasurer, county surrogate,
sheriff, and others.

District attorneys or state attorneys are usually state-level as opposed to county-level officials, but in many states, counties and state judicial districts have coterminous boundaries.

The structure and powers of a county government may be defined by the general law of the state or by a
charter specific to that county. States may allow only general-law counties, only charter counties, or both. Generally, general-law local governments have less autonomy than chartered local governments.[29]

Scope of power

The power of county governments varies widely from state to state, as does the relationship between counties and incorporated cities. The government of the county usually resides in a municipality called the county seat. However, some counties may have multiple seats or no seat. In some counties with no incorporated municipalities, a large settlement may serve as the county seat.

Minimal scope

In New England, counties function at most as judicial court districts and
sheriff's departments (presently, in
Connecticut only as judicial court districts—and in
Rhode Island, they have lost both those functions and all others), and most of the governmental authority below the state level is in the hands of
towns and cities. In several of Maine's sparsely populated counties, small towns rely on the county for law enforcement, and in
New Hampshire several social programs are administered at the state level. In Connecticut, Rhode Island, and parts of Massachusetts, counties are now only geographic designations, and they do not have any governmental powers. All government is either done at the state level or at the municipal level. In Connecticut and parts of Massachusetts, regional councils have been established to partially fill the void left behind by the abolished county governments.[d] The regional councils' authority is limited compared with a county government—they have authority only over infrastructure and land use planning, distribution of state and federal funds for infrastructure projects, emergency preparedness, and limited law enforcement duties.

Moderate scope

In the
Mid-Atlantic and
Midwest, counties typically provide, at a minimum, courts,
public utilities, libraries, hospitals,
public health services, parks, roads, law enforcement, and jails. There is usually a county registrar, recorder, or clerk (the exact title varies) who collects
vital statistics, holds elections (sometimes in coordination with a separate elections office or commission), and prepares or processes certificates of births, deaths, marriages, and dissolutions (divorce decrees). The county recorder normally maintains the official record of all real estate transactions. Other key county officials include the
coroner/
medical examiner,
treasurer,
assessor,
auditor,
comptroller, and
district attorney.

In most states, the
county sheriff is the chief law enforcement officer in the county. However, except in major emergencies where clear chains of command are essential, the county sheriff normally does not directly control the police departments of city governments, but merely cooperates with them (e.g., under
mutual aid pacts). Thus, the most common interaction between county and city law enforcement personnel is when city police officers deliver suspects to sheriff's deputies for detention or incarceration in the county jail.

In virtually all U.S. states, the
state courts and local law enforcement are organized and implemented along county boundaries, but nearly all of the substantive and procedural law adjudicated in state trial courts originates from the state legislature and state appellate courts. In other words, most criminal defendants are prosecuted for violations of state law, not local ordinances, and if they, the district attorney, or police seek reforms to the criminal justice system, they will usually have to direct their efforts towards the state legislature rather than the county (which merely implements state law). A typical criminal defendant will be arraigned and subsequently indicted or held over for trial before a trial court in and for a particular county where the crime occurred, kept in the county jail (if he is not granted bail or cannot make bail), prosecuted by the county's district attorney, and tried before a jury selected from that county. But long-term incarceration is rarely a county responsibility, execution of
capital punishment is never a county responsibility, and the state's responses to prisoners' appeals is the responsibility of the
state attorney general, who has to defend before the state appellate courts the prosecutions conducted by locally elected district attorneys in the name of the state. Furthermore, county-level trial court judges are officers of the judicial branch of the state government rather than county governments.

In many states, the county controls all
unincorporated lands within its boundaries. In states with a township tier, unincorporated land is controlled by the townships. Residents of unincorporated land who are dissatisfied with county-level or township-level resource allocation decisions can attempt to vote to incorporate as a
city,
town, or
village.

A few counties directly provide
public transportation themselves, usually in the form of a simple bus system. However, in most counties, public transportation is provided by one of the following: a
special-purpose district that is coterminous with the county (but exists separately from the county government), a multi-county regional transit authority, or a state agency.

Broad scope

In
western and
southern states, more populated counties provide many facilities, such as airports,
convention centers, museums,
recreation centers,
beaches, harbors, zoos, clinics,
law libraries, and
public housing. They provide services such as child and family services, elder services, mental health services, welfare services, veterans assistance services,
animal control,
probation supervision, historic preservation, food safety regulation, and environmental health services. They have many additional officials like
public defenders, arts commissioners, human rights commissioners, and planning commissioners. Finally, there may also be a county fire department and even a county police department (as distinguished from fire and police departments operated by individual cities, special districts, or the state government). For example,
Gwinnett County, Georgia, and its county seat, the city of
Lawrenceville, each have their own police departments. (A separate county sheriff's department is responsible for security of the county courts and administration of the county jail.) In several southern states,
public school systems are organized and administered at the county level.

Population

The average U.S. county population was nearly 100,000 in 2015. The most populous county is
Los Angeles County, California, with 10,170,292 residents in 2015.[32] This number is greater than the populations of 41 U.S. states, and even about 900,000 larger than the population of the 10 lowest states combined. It also makes Los Angeles County 17.4 times as large as the least populous state, Wyoming.

The second most populous county is
Cook County, Illinois, with a population of 5,238,216.[32] Cook County's population is larger than that of 28 individual
U.S. states and the combined populations of the six smallest states.[32]

In the 50 states (plus D.C.), a total of 981 counties have a population over 50,000; 592 counties have a population over 100,000; 137 counties have a population over 500,000; 45 counties have a population over 1,000,000; and 14 counties have a population over 2,000,000. At the other extreme, 35 counties have a population under 1,000; 307 counties have a population under 5,000; 709 counties have a population under 10,000; and 1,492 counties have a population between 10,000 and 50,000.[32]

Area

At the
2000 U.S. Census, the
median land area of U.S. counties was 622 sq mi (1,610 km2), which is two-thirds of the median land area of a
ceremonial county of England, and a little more than a quarter of the median land area of a French département. Counties in the western United States typically have a much larger land area than those in the eastern United States. For example, the median land area of counties in
Georgia is 343 sq mi (890 km2), whereas in
Utah it is 2,427 sq mi (6,290 km2).

The most extensive county or county-equivalent is the
Yukon-Koyukuk Census Area, Alaska, with a land area of 145,505 square miles (376,856 km2). All nine of the most extensive county-equivalents are in Alaska. The most extensive county is
San Bernardino County, California, with a land area of 20,057 square miles (51,947 km2). The least extensive county is
Kalawao County, Hawaii, with a land area of 11.991 square miles (31.058 km2). The least extensive county-equivalent in the 50 states is the
independentCity of Falls Church, Virginia, with a land area of 1.999 square miles (5.177 km2).[3] If U.S. territories are included, the least extensive county-equivalent is
Kingman Reef, with a land area of 0.01 square miles (0.03 km2).[1]

Geographic relationships between cities and counties

In some states, a municipality may be in only one county and may not annex territory in adjacent counties, but in the majority of states, the state constitution or state law allows municipalities to extend across county boundaries. At least 32 states include
municipalities in multiple counties.
Dallas and
Oklahoma City, for example, both contain portions of five counties.
New York City is an unusual case because it encompasses multiple entire counties in one city. Each of those counties is coextensive with one of the five
boroughs of the city:
Manhattan (New York County),
The Bronx (Bronx County),
Queens (Queens County),
Brooklyn (Kings County), and
Staten Island (Richmond County).

^ The
Unorganized Borough, Alaska formed by the Borough Act of 1961 is a legal entity, run by the Alaska state government as an extension of State government,[16] it and the independently incorporated Unified, Home Rule, First Class and Second Class boroughs roughly correspond to parishes in Louisiana and to counties in the other 48 states.[17]

^ These 11 statistical areas are used solely by the
United States Census Bureau to tabulate population and other census statistics within the Unorganized Borough; they have no legal basis in Alaska state or federal law other than for electoral representation and federal financial assistance purposes.

^Unlike in Massachusetts, Connecticut's regional councils do not conform to the old county lines, but rather, they are composed of towns that share the same geographic region and have similar demographics.